The update brings fluid simulation tools to load and save presets including the addition of several built-in common fluid types, improvements to the UI, and more.
3ds Max Fluids has been updated with usability improvements based on your feedback. As the simulation is being run, Max Fluids now displays the frame number, instead of the percentage of completion, as well as other information about the simulation from the output window. Other improvements include the ability to apply UVs to the output mesh, setting an initial simulation state, or removing unwanted time from the simulation.
3ds Max 2018.4 now includes fluid presets, making it easier to add fluid simulations to a scene. The included presets consider viscosity from a wide range of common fluid types, from thin liquids like water to thicker liquids like chocolate syrup, honey, and ketchup. Users can also create and save custom settings as presets to more quickly re-use desired fluids in other scenes.
You’ll notice improvements to 3ds Max Interactive, the VR engine added previously in the 3ds Max 2018.1 update.
3ds Max Batch has been redesigned to provide a simpler and more effective experience. It is now a true command line productivity tool, with logging and error reporting, it supports user-defined messages in the output, and allows users to inject data in the automation process from the command line.
More details can be found here. Over 100 bug fixes reported by user are listed in the release notes.